The present invention concerns a device for direct refrigeration of a component of a system or the entire system by which a cooling intermediary, such as methanol or other liquid can be avoided, and, in another embodiment, a refrigeration device, which, in general, employs opposing refrigeration flowpaths in a cooling block. Heating may be conducted. Such can be employed in conjunction with a solid block, thermoelectric device to enhance heat transfer cooling, and/or temperature control with the Peltier effect. The invention is useful especially in direct cooling and/or temperature control of solid components, which, in one embodiment, can be part of an instrumental system for low temperature viscometric testing of engine oils and so forth, say, to determine yield stress and apparent viscosity of the oils; and, in other embodiments, can be for various other applications as, for instance, to cool various heat-emitting electronic components, centrifuges, industrial machinery, and so forth.
The performance of engine oils and other lubricants at low temperatures has been of increasing concern, and various art has been developed in order to ascertain, in advance, properties of the oils which would be determinative of the likely success or failure of the oil under low temperature operating conditions, especially in start up and cold temperature operation of motor vehicle internal combustion engines. In the testing of engine oils at low temperatures, it is critical for performance of the test that the test oil be maintained at a particular temperature and/or be controlled to have a certain rate of increase or decrease in temperature. For example, ASTM D-4684-98 covers the determination of yield stress and apparent viscosity of engine oils after cooling at controlled rates over a period exceeding forty-five hours to a final test temperature of between minus fifteen and minus thirty-five degrees Celsius. That standard test method specifies circulation of liquid coolant, for example, methanol, to cool the test block and, in turn, the test cells.
In addressing such requirements, certain devices have been provided. For example, the standard instrument in its field for the ASTM D-4684 test method is the Mini-Rotary Viscometer (MRV) from Cannon Instrument Co., State College, Pa. Developed in the 1970s, the MRV in general provides for a rough viscometric method to obtain data under low temperature conditions at, however, only one temperature at a time. The MRV has an aluminum block, which temperature is controlled by a refrigerated methanol bath that requires a circulating system to pump the coolant from from the refrigeration device to the block, and back again to the bath to cool the block. A temperature-controller in the aluminum block is employed to attempt to hold the temperature at the programmed set temperature. Among drawbacks further may be mentioned a lack of precision and accuracy, as cooling of the aluminum block by the cooling fluid is carried out along a flow path through the block. Accordingly, the MRV block is cooler at its cooling fluid entry end than at its exit end, notably because of temperature gain from the environment of the room; this effect is exaggerated at colder test temperatures. Thus, in general, the temperature so necessary to development of accurate data for sooted and/or highly oxidized oils is not held well by today""s standards, with, for example, a five-degree Celsius temperature differential from end to end of the instrument often found. And, water in MRV test cells can be problematical, especially at low temperatures, with xe2x80x9cfrostingxe2x80x9d an impediment, and in consideration of its test cell design with a xe2x80x9cwellxe2x80x9d raised above the bottom of the cell. At the lower temperatures, the MRV weaknesses noticeably show. Also, the use of methanol, a hazardous material, can be problematical from standpoints of laboratory practice and personnel safety.
An improvement is the device to test pumpability of oils at low temperature of Selby et al., U.S. Pat. No. 5,852,230. With the device of Selby et al., all stators that are filled with test fluid can be positioned in a carousel arrangement, which can be immersed into a temperature control bath, and held at the same temperature through a spaced-apart stator array and the mobility of the temperature control bath fluid, for example, methanol. As a result, test accuracy and precision are notably advanced. As well, among other things, with that device, a greater number of test cells can be tested simultaneously. However, the device has need of an intermediary bath, which again is typically methanol.
Moreover, many devices or components in devices which generate their own heat can be damaged or have inferior performance through excessive heat. For example, CPU chips require cooling, which is provided by relatively inefficient air fans, to remain operable; and known superconducters depend upon cold temperatures to be operable.
It would be desirable to improve upon the foregoing.
In a basic, and desirable aspect, the present invention provides a device for direct refrigeration comprising a heat-conductable solid member having a refrigerant passageway coursing through or about, and at least one of the following:
at least one test sample well therein or in proximity thereto;
at least one solid, heat-generating member affixed or in proximity thereto; and
optionally, additional component(s) and/or feature(s).
In another aspect, a heat-conductable solid member may have opposing refrigerant flowpaths coursing therethrough, said flowpaths containing conventional cooling material(s), for example, cooled air, or liquid methanol or ethylene glycol, but preferably, a refrigerant for direct refrigeration. The member may be, for example, a block of copper and/or other material with a high heat-conductance, with one or a plurality of test sample well(s) for insertion of viscometric test sample cell(s) for viscometric or other type testing. Heating may be employed in conjunction therewith. Accordingly, the device can be adapted for use in a test to determine yield stress and apparent viscosity of engine oils at low temperature by providing a rotor, and optionally, but preferably, a test cell sleeve, for insertion in a respective test sample well. Dynamic temperature control can be facilitated by a temperature sensor and/or controller system, with sensor(s) and/or heating element(s) strategically placed in or on the block. The device may be augmented or conjoined with or to a solid block thermoelectric cooling/heating contrivance which operates by the Peltier effect. Beneficially, the block is made of a generally inert material, for instance, a metal, with a high heat conductance, for example, copper or gold. A special, radially endowed correspondent cell pin and rotor bottom cup arrangement can for practical purposes provide nearly friction free action, essentially unencumbered by water/ice interference, and a unique dry gas blanket delivery system can be provided. As well, unique rotor key arrangements can be provided. Other aspects include methods of use of the device.
The device is useful in cooling, temperature control, and, in certain particular embodiments, fluid characterization testing.
Significantly, by the invention, problems in the art are ameliorated, if not eliminated or overcome. Not the least of these is the elimination of intermediating cooling liquid, such as methanol, if so desired. Thus, the device can be made to be more compact, efficient to make, and very easy and efficient to use including in set up, running, controlling, and cleaning, and free from the hazards which attend the use of methanol. Air or liquid cooling of electronic to include computer or mechanical parts is also improved by the direct cooling. As if that were not enough, exacting, nearly pinpoint standards of temperature control with the device are achieved if not set outright, and, with a dynamic temperature regulating system, the device can be used in obtaining data through accurately and precisely scanning a range of temperature rather than being limited to one temperature per test. Such high standards of temperature control with the device can occur through employment of the opposing refrigerant flowpath system. Embodied for employment in a test to determine yield stress and apparent viscosity of engine oils at low temperature, operation of and data collection of plural samples with the device are greatly improved by a radially arranged sample well array such as the radially endowed correspondent cell pin and rotor cup system. As well, the unique dry gas blanket delivery system, in addition to the cell pin and rotor cup system, can ameliorate if not eliminate the impediment of xe2x80x9cfrosting.xe2x80x9d The unique key arrangements and other features can facilitate greater efficiency in testing as well. Individual cell control can also be achieved by single cell cooling and temperature control. Moreover, the Peltier effect can be put to advantageous use without the need for exotic refrigerants or excessive mechanical refrigeration cascades so that cooling with more standard refrigerants can be lowered forty degrees C. With such solid block thermoelectric cooling/heating contrivances, in general, a range of eighty degrees C can be modulated by and/or used as a modulator for the cooling provided by the direct refrigeration device. Also, various heat-emitting electronic components, centrifuges and machinery can be cooled directly. For example, superconductors or superconductive devices can be cooled directly as well as can be computer component, such as computer processing unit (CPU) chips and mainframe boards; cryogenic devices; other types of heat-emitting electronic components; centrifuges; pumps; metal-cutting and injection-molding machinery; clamps; bearings; and so forth. In fine, the invention may be employed nearly anywhere a component or system, especially that which includes a solid member, which may generate its own heat, needs cooling and/or temperature control.
Numerous further advantages attend the invention.
The drawings form part of the specification hereof. With respect to the drawings, which are not necessarily drawn to scale and in which, if dimensions are listed, they are listed in inches (xe2x80x3) unless otherwise noted (with dimensions typically taken to places, such as X.XXX to +/xe2x88x920.002; X.XX to +/xe2x88x920.010; fractions to +/xe2x88x921/32; angles to +/xe2x88x921-degree) and are to be considered exemplary and may be considered approximate or to be varied from in the practice of the invention, the following is briefly noted: